Cracking still



Nov. 5, 1929.

CRACKING STILL Filed March 4, 1922 l s sheets-sheet l G. l.. PRlcHARD ET AL l1,734,827

N0V- 5, 1929. G. l.. PRICHARD ET'AL CRACKING STILL Filed March 4, l922 6 Sheets-Sheet 2 QN. @d

NOV- 5, 1929- G.L. PIRICHARD ET Al. 1,734,827

CRACKING STILL Filed March 4, 1922 6 Sheets-Sheet 3 imm@ NOV' 5 1929- G. PRICHARD ET AL 1,734,827

CRACKING STILL Filed March 4, l922 6 Sheets-Sheet 4 Nov. 5, 1929. G. L. PRICHARDET AL 1,734,827

CRACKING STILL Filed March 4, 1922 e sheets-sheet 5 FEGLA 70H Nov. 5, w29. G. L. mica-:ARD ET AL 1,734,827

CRACKING STILL Filed March 4, 1922 6 Sheets-Sheet 6 ed verticalboiling su ts whenever a petroleumoil is heated above a certain temperature, v15

` above the normalboiling p as regards heating.

Vina-ata Nav. 5,1929" PATENT- OFFICE GEORGE I..V

. sIGNons- "ro rom'rIoN or Taxes rmciunn AND HERBERT HE l NnEnsoN, GULF nEmNnIG COMPANY,

Icnacknicf s'rILL I p Ap'pncaeon mea umn 4, ymaa serial 110.541,126.'

This vinvention relates t0 cracking stills; and it comprises a cracking still having a comparatively -large hot oil chamber, lateral heatand circulatingtubes connected with said oil chamber at their top an bottom, from said hot oil chamber, and .condensing means receiving vaporsr from the dephlegmator; all as more fully hereinafter set forth and as claimed..

In a general way in with productlon of low boiling oils reoften arbitrarily set as being about 7 50 F. Oils maybe cracked in either a liquid or a vapor form; but in the former case, if the temperature selected is point, pressure must be used. Many methods and apparatus embodying vthese principles have ,been proosedand several are inuse.

It is the purpose of the to provide a simple and e ective apparatus, economical of heat and capable of being run for a long eriod of time without the necessity of being c eaned'out.v In cracking oils there is always a productionof carbon and this carbon tends to deposit on the heating surfaces,

resent invention impeding further transmission of heat and roducing various (buckling of plates, cracking stills, as a rule, are'not economica other inconveniences etc.). For this reason invention, heating is per- In the present element consisting formed in a special heating of vertical tubes in a sultable re chamber;

a plurality of tubes being mounted in parallel and connected to suitable drums or headers lat the top and bottom.

ment 4is suspended vent the inJurious effects ofe'xpansion an contraction and the oil is substantially` uniormly heated throughout vthe tubes. The two headers are connected laterally to one or more vertical surge chambers, or hot oil chambers, of comparatively large capacity. The top header connects with'a surge chamber at a point somewhat' therein. llVith'this arrangement a very active upward circulation is createdin the heat- The whole arranged, circulating lsystem. a dephle'gmator receiving vapors it may be said that crackstripping or topping 1 vchamber are below the normal oil level l from and to the surge chamber, through theheating tubes. The tubes form the hot leg, 4the .surge chamber the cold leg of the vIn the heating tubes the boilin of the, oil creates ay mixtureof liquid an vapor Ipassing violently upward and givinglittle opportunity for deposition of carbon on the walls, passage of liquid and vapor along the tube walls, the heating eiiiciency of the tubes be- 'comes very great. The mixturel of oil' and vapor passes vinto the surge chamber below the normal level therein and gives up vits heat 1n large part to the oil. When the apparatus is 1n operation, of oil in the surge chamber is raised to such a point as will vaporize Anaiphtha and allow its vapors topass forward, while eiect-ively condensing heavier oils. oil as may be in the oil supplied to thesurge chamber is` volatilized and passes forward with thelow boiling oils formed in cracking. As will be noted, with this 'surgeachamber is at once a ing the system, and j holding back the heavy oils. tem may operate under as ymuch pressure as ma be desired.

he vapors passing led through a dephlegmator and thence to water-cooled condensers in the usual way. y

In the accompan ing drawingsv we have shown two forms o apparatus useful inthe while with the rapid..

the temperature of the body Such low boiling arrangement the heat exchanger, a y device for the oil enterafractional condenser i The whole systubes; the oil flowing in cyclic circula- I tion,

performance of-our process and within the y purview of our invention. Y

In these drawings, Fig.=1 is a side elevation with parts in section and constituting more or'less a diagrammatical showing of the equipment forrperrormin the process;

Fig. 2 is a top plan vlew of ig. 1, certain parts being shown in section;

Fig. Fig. l on an enlarged scale; A

Fig. 4 is a detailed a lower drum of the still of Fig. `1;

Fig. 5 is anenlarged section partly in. elevation showing the valve in the surge tank;

3 is a vertical'section along line 3-3 of longitudinal section of lor roar ARTHUR, or PITTSBURGH, rENNsYLvANm, A com 15" to the bottom of these lugs.

-ture is different form` of in Fig. 1; and

' F 1g. 7 is a vertical section through theV furnace, showing the means for controlling there gases. u A

The stilll is specially designed and comprises the supports 1 bridged as at 2 and havlng the rods 3 secured to the bridge by means' of the boltsv 4. Thissupporting superstrucpreferably of angle iron construction. The upper vpart of thebrick casing 6 above the fire box and around the heating element is hung to the drum 16 by lugs 20 riveted to the drum, and by upper channel irons 5 bolted lower bricksupporting lugs 5 and 7 are bolted to the boiler plate 9. g The whole boiler-like arrangementtogether with the upper brick work 6 is thusv suspended from lthe standards 1, and expansion and contraction-well taken care of. Asbestos packing may be used betweenthe upper part of the fire box and the sus ended brickrwork 6. Certain of these fire rick supporting angle irons, such as 7 are lon er than others to supfport layers of the bric ,as at 8,'in order toy orm baiiles inside the furnace., The structure described, togetherwith'thel bridge wall 102 the sus- -pended atarch 11 v stitutes theentire heating device for the still 4to be described. The fu `tubes 18. The upper drum or rnace may be fired by an oil or .other burner, -diagrammatically shown at 13.v The flue 14leads to the stack.

' Mounted inthe heating devicefis the still 15. Thisstill comprises the Vupper and lower drums`16 and 17, respectivelyljoied by the ea 16 is pro.-

vided with a plurality'of ears 19 to which the `rods3 are secured. This'construction results in theprovisio'nolf. .a still suspendedin the heating device. To assist in supporting the brick, the angle irons and braces 2O resting on the to angle irons 5 may be used. The upper an y lower drums, or still heads are `in ,communication through the tubes 18. -The lower head isvtprovided interiorly with car'- bon or tar shel 21 (clearly shownin Fig. 4). This shelf 21 may be suspended orsupported in the drum. Itis shown supported by the legs 22 suitably braced by rods 23. l This shelf,

being directly under the tubes 18, receives the carbon and heavy tar which is cleaned from' .these tubes by the use of the usual boiler tube cleaning devices. When this cleaning is done, the manhole cover ma be-rexnoved from the end 24 and the auxiliary shelf 25 may be placed in position to form a continuation of the shelf 21, so that tar and carbon and heavy residue collected and deposited upon the shelf 21 may be scra ed out of the lower still head.

Line 26 may ead from the bottom of the lower still head for conducting heavy liquid material to thecooling box hereinafter described,

pparatus than that shown The upper and Y and the furnace 12, con-.

`In operation, should any of the tubes leak or for any reason break, the bottom floor 27 of the furnace isv rovided with'the drawof line 28 leading to t e trap 29, with the bridge wall 30 for preventingadmission of air and gases and thence from said trap through pipe l 31 tothe sewer.- The trap 29 is a fire trap'.

In communication with the still is the surge tower 32 (one or more may be used) having the pipe 32 in communication with the lower still head 17 throughthe hydraulic valve 33, and I'eadingfrom the top ofthe upper still head 16.v is the vapor' line 34 provided. with the safety valve 35 and vhaving hydraulic gate valve 36. f f

The surge tower 32 `is provided with a charge line 37 which terminates inside the tower in,` a valve 38. The line may have a handy valve y39 outside the tower. l valve 38 is provided with av gear 40 (see Fig. .5) and this gear is adapted to mesh with a The inside' sliding rack 41 riding in the ring 42 which,

Oil from the surge tankgiis delivered to the bottom' still head` 17 through pipe 32. Vapors from the' upper still surge tower advantageously below the level of the oil therein through the line 34 andl leave the surge tower through line 45 provided` with ead enter the a safety valve 46. From this i line the vapors (in Fig. 1) go tothe dephleg- 'l mating tower 46and from 'thence they How through line 47 to the condenserA box 48. Condensate from the dephlegmating tower goes tothe cooling box 49 through line 50. The cooling box 1s' mounted on a suitable foundation'51and from it, by line 52, thecondensate goes to pumps and thence to tanks not shown. The condenser box is advantageously mounted upon the foundation 53 and is provided with a line 54 leading past trap 54 to a storage tank for the condensates. The gas may go to a gas vcompressor (not shown) through line 55.

For the purpose of relieving the pressure to the dephlegmating tower and for controlling the pressure on the still, we provide regulator, such as the well known Mason regulator, 'on the line 45 leading from the surge tower 32 to the dephle mating tower 46, this regulator having an' independent pipe connection to a point in the vapor space of the surge tower. This regulator is shown diagrammatically at 56, .the regulator itself form of lapparatus.

. in the surge tower.

In Fig. 6 is shown in elevation a modified This closely resembles the apparatus previousl described, and its operationis the same. o wever, in Fig. 6, we have .shown the dephlegmator 46 at a higher elevation than the surge tower 32, such dephlegmator bein mounted on the supports 60 and provi edwithreux or backtrapping line 61 leading to the surge tower. In this view we may use a Mason regulator 'for the vapor line 47 leading from the dephlegmator.

In Fig. 7, we have shown a modified form of furnace., In cracking oils, itis highly desirable that there should be a uniformptemperature through the body of oil undergoing cracking. To accomplish this purpose, we have provided ourfurnace shown in Fig. 7 with the tall fire box. 62'having a plurality of vertically spaced flues 63 rovided with sliding dampers 64. Imme flue 63 is located the baille plate 65, and an additional baille plate 66 is locatedtowards the top of the furnace chamber, these bailles causing circulation around the tubes. Eosite side of these haines,

er is provided with a series of shelves 67 holding the baille plates 68. By a proper adjustment ofthe sliding valves .64 the lire gases can be sent to any point along the height of the tubes and if there is local overheating at any point along the tubes,

nace may be provided withA door moval of tubes, etc. Yan'd with the eep holes 69 for observation of temperature y color.

In ordinary boiler heating, the purpose is to supply the/products of combustion or heating gases at a relatively high temperature and to absorb as many heat units as posisble, exhausting the gases at as low a temperature. as possible. According to our invention; in cracking oil the re Igases are supplied at the cracking temperature throughout thev wh'ole length of the heating surface and, therefore, are not reduced in temperature in the same ratio as gases used for heating boilers. According to our invention, these hot gases, be- -forereaching the stack through flue 14, may be sentto thev superheater orprcheater 70; in which may be located coils -71 leading to the supply line for the cracking furnace.

Higher boiling hydrocarbons, such as gas oil and the like, to be cracked are delivered under pump pressure to the surge tower 32 by line 37, valve 39being open. When the float 44 in the surge tower reached a predetermined height, the rack attached thereto operates the pinion 40, closing the valve 38. When tower.

l 650 F: to 1400` F. or 1500 iately below each.

On theol oil may be caught in the furnace chamthe lire` gases can be shut off at such point.' The fur- 69 for re- .admitted to theiioat descends, the valve is ppened. This provides automatic control of oil to the surge above the normal oil level in the surge tower.

The oil from the surge tower passes by line 32 to the lower drum 17 and fromsuch drum up past the furnace gases the plurality of tubes 18. The oil is heated There should be sufficient vapor space while confined in to a cracking temperature which may be from f F., or and then passes to the drum 16, mostly as vapor. From the drum l16, thevapors pass to thesurge tower 32 which is located belowv oil in the surge tower. As lis'illustrated in Fig. 2, two surge towers may be'- used." The waste gases pass through flue 14 to the stack. When the formshown in Fig. 7 is used, the ases are controlled so as to secure even heat-` ing along the length of the tube by aproper higher,

through vapor line 34 he normal level of the manipulation'of the slide valves 64. Thel y gases' may pass tothe superheater 7 0 wherein arelocated the coils 71. These coils may be j connected with the source of .supply-of oil and may lead 'tot-he' line 37 of the surge tower. In case the tubes, or one ofgthem, *should break, the hydraulic gate valves33 and 36 are immediately closed and only the oil in the tube heater is lost from the system. l This the basin immediately below the lower drumean'd -sent'by line 2811.0 the trap 29 and thence to a point of use or to fthe sewer through line31. The valves 33v and 36 prevent loss of oil from the surge tower. The trap 29V is lprovided 'with the' downwardlyprojecting ate 30'which will prevent passage of flame in event o f lire in the furnace proper.'

The surge towers 32 lare provided with safety valves 46 dephlegmator vided with a stem operatingtheval've Ito thel stem being controlled by l Aa piston in a cylinder and the pistonI being i dephlegmator, such moved by. the pressure of the vapors in" the line 45 or in the sur e tower 32. This regulator may be set so t at the-vapors enter the and the vapor-lines 45 lead-' ing to dephlegmator 46. In order thatthe pressure or the velocitiy)1 Jofthe vapors to the dephlegmator at a-.predetermmed ate, ve-

locity or pressure. vanta eous This is particularly adbecause the uniform operation or function of a dephlegmator is easily dlsturbed by fluctuations in the amount or ressureoft e vapors entering it. Va ors rom the dephlegmator Vleave y line 4 andgo to the nal or water cooled condenser 48. The lower boiling hydrocarbons condensed flow past the trap 54' by line 54 to stock storage tanks (not shown) Uncondensed gases pass through line 55to the burners or to other points of use. Sludge and heavy residues isol from the dephlegmatoripass to the cooling box 49 through line 50. When the still is shut down and it is desired to remove the oil or when it is desired to remove heavy residue such as tar or sludge from Athe still t-he valve on line 26 may be opened and lsuch tar sent to coils in the cooler 49, thegate valve on lline 3,4"being closed. `The residue or sludge K in the surge towers settling to the bottom is removed continuously or at intervals through lines 26 and sent to coils in the cooling box 49. p

In Fig. 4, we have shown on an enlarged scale and-.in longitudinal section, the lower drum 17. When the tubes are to be cleaned, the head is-taken off the end 24 of the drum `and the short shelf 25.is inserted so that it f forms a continuation of the shelf 21. The

tubes, being directly over thisI shelf, the carbon falls upon.the shelf when the tubes are cleaned and may be easily raked out with a hoe or the like.

In Fig. 6, the dephlegmator is at a higher elevation than the surge tanks and, if desired, the pressure may be maintained constant in the dephlegmator by means of the Mason regulator on the va or line 47 The condensates from the deph egmator flow by run-back a fire box and a heating chamber in communi-` cationtherewith, supports, a still comprising 4o an upper'and lower drum connected by tubes and vsuspended inthe heating lchamber by thesupports, and fire brick or the like surrounding the still and suspended therewith above the level of the fire box.

y 2. Apparatus for cracking oils comprising `a fire box and a heatingchamber in communication therewith, supports, a still suspended in the heating chamber by the sup-y ports, a irebrick lining for the heating chamber attached to and suspended with the still, said lining being immediately above the lire box and baflles carried by the fire brick wall and in the heating chamber to cause circulation of fire gases around the still.

3. A paratus for cracking oils comprising a fire ox and a heat-ing chamber in communication therewith, supports, a drum carried by said supports, tubes depending from said drum and extending through theheating chamber and a lower drum at the end of said tubes, fire brick or the like-suspended from the first said drum and surrounding the upper part of the tubes and constituting the upper part of the heating chamber, said` suspended lire brick being separate from the v 4. Apparatus for cracking oil comprising a vtubular boiler-like arrangement having upper and lower drums connected'by a plurality of tubes, supports for the upper drum,

means attached to the'upper drum for sup.l porting lire brick or the like, and fire brick means at alower point in thel surge tower for supplying vliquid oil to the still, a de- -iphlegmator in lcommunication with` the surge tower,

and means operated by the pressure in the surge tower for controlling the rate of. flow of vapors therefrom to the dephlegmator.

6. Apparatus for distilliug oil comprising upper and lower drums connected by a plurality of tubes, and firing means, the lower drum being provided with an interior shelf directly under the tubes for receiving' carbon and the like cleaned from said tubes.

7. Apparatus for distilling oil comprising upper and lower drums connected by aplurality of tubes, and firing means, the lower drum being provided with an interior shelf directly under the tubes Yfor receiving carbon and the like cleaned from said tubes, and an additional shelf arranged to form an extension of the shelf contained in said lower drum, and adapted to be used for raking out material deposited on theshelf in the drum from said tubes.

Signed at Port Arthur, Texas, this 28th day of February, 1922,

' GEORGE L. PRICHARD.

` AHERBERT HENDERSON.

generated by the still to the surge tower and 

